240 Total Loss of Power + Rough Idle (91 Volvo 240)

Greetings! I’ve enjoyed reading other people’s threads for a while now and learned a lot from you guys … I really appreciate and respect the knowledge shared here. After spending the last several months fighting a Volvo issue and reading every thread I could find on the topic across several forums, I decided to ask my question directly.

My Car:
’91 Volvo 240 B230F (non-turbo)

The Problem:

• Going back ~1 year, I started having random instances where my Volvo would be reluctant to accelerate. I would step on the gas but the acceleration would take a moment to fully “catch.” No big deal.
• In June of this year (2017) my main fuel pump died on a road trip and was replaced by a mechanic.
• Immediately after the fuel pump replacement, I started having more trouble with acceleration and even stalled multiple times when rolling to a stoplight etc.
• When I arrived home in early July, I took the car to my local mechanic (great guy ... only works on volvos) he fixed the in-tank pre-pump and we thought the issue was solved … it wasn’t!
• On the way home from the mechanic, the car stalled 3 times while traveling at ~40-50mph. By stalled I mean, total loss of power while my foot was still on the gas pedal. I could get the car started again but only with a lot of gas feathering and patience.
• Once home, the car has been very reluctant to start and will stall when the accelerator is depressed with anything more than a very gradual pressure. NO power at all in acceleration.
• 3 months and lots of DIY work later, my beloved Volvo is still very reluctant to start and will only idle for 5 minutes before the engine starts shaking heavily and stalls. Can’t even get her on the road to get to the mechanic.

What I’ve Done:

• Replaced fuel pump relay
• New main fuel pump (by mechanic in June)
• Repaired fuel pre-pump
• Cleaned Engine Idle Control Valve/Switch
• Checked/Set throttle switch
• Cleaned Throttle Body
• New Air Mass Meter
• New Fuel Pressure Regulator
• Checked/Cleaned fuse connections
• New spark plug wires (plugs are <1 year old)
• New O2 sensor

My Skill Level:
I’ve owned this car for 5 years and my dad bought it new in 1991. I’ve worked on this car all my life and know it pretty well; general maintenance as well as the occasional bigger project. This issue has me stumped though and I’d appreciate any ideas.

Let me know if you need any additional info and thanks in advance for the assist!

Cheers,
Garrett

Forgot to mention that I also checked for error codes. I was getting the code for a faulty AMM until I replaced it. Now I just get 1-1-1. If only that were true!

I also replaced the O2 sensor.

Clogged fuel filter? Unplug a rail and see how your injectors are spraying.
Wanna bet $100 on fuel, then replace fuel filter and get something like this (verify part number on injector): http://r.ebay.com/rQCgJH
If that won't help then start looking into vacuum leaks and ignition/spark.
I drive with those for already 2 months, seems fine.

Thanks for the ideas! I picked up a new fuel filter today and was planning on getting replaced on Friday. The current filter isn't that old though.

As for the fuel injectors, I'll take a good look at that. Hadn't thought to check that yet; I'll get back to you on that front.

Really hoping it's not a vacuum leak but I guess that's the next thing on the list.

I know you already discounted them, but pull the sparkplugs and check their appearance. If they're black and oily, or sooty and/or damp with fuel - replace. (Your edit: last THREE points - sound very similar to my 91 240's behaviour with fouled plugs, from overfueling due to a failed O2 sensor.)

Most likely point of failure is the crank sensor.

Second most likely is the power stage.

Or somewhere in there, LH/Fuel pump relay.

Oh and fuse corrosion is common. Clean. While on the topic, make sure ground wires at fuel rail are clean and tight.

Good afternoon,

I finally had time today to work on the car and try the suggestions you all gave.

-Started off cleaning the spark plugs: dirty but not too bad.
-Checked all grounds and re-checked fuse connections.
-Next, I replaced the fuel filter. Not hard at all ... once I got the banjo fittings apart

Did all this and the car was still very reluctant to start. I went back down under the car to make sure I did everything right with the filter. While I was down there I noticed that the fuel line (leaving the filter) had a kink just past the clip holding it to the car. I worked the kink out and slid the fuel line down a bit (so the clip would keep the line straight) ... and the car started right up and idled beautifully for 30 minutes! It revs w/o hesitation and the main pump sounds much quieter.

My guess is the mechanic who replaced the pump let the whole assembly hang from the fuel line rather than supporting it as you're supposed to grrr. Fingers crossed but I'm hoping this is my solution. I'll check back and let you know how it runs in the next couple days. Thanks for all your help!

Piano Man said:

...I'll check back and let you know how it runs in the next couple days. Thanks for all your help!

Click to expand...

Was the kink the problem? I hope so!

Well, it wasn't the kink ... apparently that day of smooth running was a fluke. I spend several minutes trying to start it on Monday and when I finally got it going, the idle was a bit rough and the engine lugged up at the slightest acceleration.

I ordered a new crank position sensor and engine coolant sensor. They arrive today and I'll try and install them over the weekend. I'm starting to think this is an electrical issue?

I'll let you know what happens with the new parts in.

Try a new fuel pump relay....just for kicks.
Also, check the connections on the relay plug.

Recently found an easy way to check fuel relays - on a 1991 era anyway as it's the same as mine. Remove its plastic cover, make sure it's internals don't touch any metal, and watch the two relays as you turn the key to ignition lights on position. Both relays should latch closed, and you'll hear the fuel pumps come on. A second or two later one relay should unlatch, and the fuel pumps go off. Then turn the key off. A couple of minutes later (wait for it) the second relay will unlatch. If it behaves this way it's ok.

(And if you still have the old one, either you or get someone else to - remove the old and resolder with fresh solder. Then test it works and keep it in the glovebox.)

The behaviour you're describing when you do get it running, is the kind of thing you see when you've disconnected the battery. (Difficult to start, and when it does the ECU can take a couple of minutes to 'relearn'. BUT if there's another problem somewhere else, it may be attempting to learn, making adjustments that prevent the car starting.)

So... Next time you get it started, keep trying to get the revs up high and hold it up there for a while. If it gets noticeably better and suddenly responsive when you move the pedal up and down (behaves nearly normal except for at idle which is still rough), then check the lambda sensor (oxygen sensor) bulb in your dash is ok. If that bulb is blown, replace it, start the car again - does that light now come on? If so, obviously replace the O2 sensor.

You can also check a) that the fuel hose hasn't collapsed internally at that kink spot, b) and fuel is reaching the injector rail, therefore c) the fuel pumps are working... by pulling off a rubber hose at/near the fuel pressure regulator/injector rail area. Have someone point it into a jar while cranking the engine (and don't crank too long), so it doesn't start a fire. A good amount of fuel coming out = all those things are ok.

The CPS is a common failure. But when the car won't start you can check it by sticking a test light (two wires connected to a 12V bulb will do) into the cable of one of the fuel injectors. They're all connected together, so you only need to test one. Push the chrome wire in, pull the plug off the injector, one wire in each socket. If it flashes when you crank the engine (again - when the car won't otherwise start) then the CPS is ok. (The pulse from the CPS tells the ECU to pulse on the ground for the injectors. So if the injectors are flashing, they're working, and so the CPS too is working.)

Btw, you can do that same sort of test across the two coil spade terminals (with everything else still connected). Crank engine, bulb will flash.

Could it also be the distributor cap? My car's done something like this after sitting outside overnight in the rain. The engine started sputtering and shaking if i applied more than a tiny amount of pressure on the throttle, and I think if I'd kept holding the pedal down I would have stalled. Accelerating with any haste would also result in a loss of power. In my case, I replaced the distributor cap & distributor rotor, as well as the plugs and ignition wires. Maybe overkill, but it resolved my issue.

Could be a totally different issue, though, because my car has only stalled out while driving (due to something other than a bad shift) once - that was five years ago and it's never happened again so I guess it was a fluke.

Good morning, Thanks for all the ideas! It's been a busy weekend but I was able to do a little work yesterday.

I replaced the CPS ... and it definitely needed to be done! (see picture) The rubber insulation on the old one was all cracked and I could see the bare wire. With the new sensor in, the car actually started right up and seemed normal for about 10 minutes of idling and driving on the driveway. I thought all my problems were over until I tried to start it again a few hours later ... without success.

TheFamilyman, I'll check the fuel pump relay today if possible. It's brand new and I can hear it clicking properly when I turn the key. I'll do a visual check as you described just to make sure. Very interesting what you were saying about the ECU "learning" after the battery has been disconnected. While the car was sitting for several weeks waiting for parts, the battery died (must have been the glovebox light). I'll try what you suggested. Thanks!

The distributor cap is fairly new ... about a year/15k miles. The plugs and wires are all new too. That being said, the distributor is probably the next thing on the list.

I can smell gas after cranking the engine so I seem to be getting fuel to the engine now. Does this point to an electrical/ignition problem? Bad ECU? I'm reluctant to keep throwing money at the car without knowing what's wrong ... but doubly reluctant to loose my faithful 240.

Ok, so apparently I don't know how to post a picture using the link ... sorry guys. I'll try to figure that out and repost the cps picture.

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Have you checked your fuel pressure regulator? Pull the vacuum line on the regulator and see it it's wet or smells like fuel. If it does, the regulator is bad. Smell of fuel could be a bad regulator.

Thanks for the idea, Centason. I actually put on a new fuel pressure regulator a couple weeks ago ... didn't seem to make a ton of difference but it probably would have needed to be done soon anyways. The old unit was OEM. Gotta love Bosch parts!

FWIW, I noticed in your pic that you have an original Volvo radiator. I would replace it if you plan on keeping the car. Of the two 240's I've purchased, one radiator lasted a few months, leaking from the upper radiator opening. After further inspecting it, and trying to gently tighten it, the port crumbled and broke off in the hose dumping coolant into the driveway.

The 88 244 with a 90' Volvo radiator installed, wasn't so lucky. The radiator failed in the same spot, but on a busy highway eventually warping the head.

Just one more thing, I know.

I hope that you find your problem because intermittent ones are a challenge. Check for shorts, rubbing and corrosion in all of the suspected areas. The grey connector of the wiring harness that is attached to the firewall with a clip sometimes gets corroded.


Art also has some helpful info about adding a blade style fuse to the 91 model here: http://cleanflametrap.com/emfuse.html

What I said the other day was inaccurate. With a faulty O2 sensor it would run BETTER at high revs, would still shake and carry on a bit, and probably stall at idle.

I've owned 240s for about 25 years and never had the 'common' fuse trouble. However someone does/did sell a fuse block on that is a direct replacement, that takes glass fuses instead of the euro style. I was going to buy one just because I prefer glass fuses and thought it was IPD. But I just checked and couldn't locate it. So maybe it's not available anymore.

If someone has problems with their euro-style fuses, I don't see the sense in replacing one if you can still buy that replacement fuse block. Because you'll still have to regularly clean the other fuses. I know the fuel pump has a healthy continuous current. But the reason that fuse overheated was due to corrosion. And if one fuse in a fuseblock corrodes and creates a high enough resistance to melt the plastic, then it's just as likely more of the fuses will develop the same fault.

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1. Now the car has been running (assuming you haven't disconnected the battery which resets the ECU) are there any codes showing?
2. There was a changeover in 1991 where some 240s had the 25A fuse in the engine bay and some didn't. Check if yours has it. The most common (factory) location is on a bracket (the voltage rail) behind the battery.
3. Symptoms of a faulty Ignition Amplifier Module: Car runs ok for a while, module gets hot, car dies and won't restart. Module cools down, car will start again. If completely dead car will crank but not start. (You can probably test this before replacing, with a can of freezer spray from an electronics store.) https://www.fcpeuro.com/products/volvo-saab-porsche-ignition-module-3501921

When the car won't start:

4. It's probably not the pumps or fuel relay, but you can still hear the fuel pumps come on for a couple of moments with the key, right?
5. Does jumpering fuse 4 & 6 run BOTH pumps? (Don't leave it connected for long.) If you're not sure, you can remove the plastic cover in the trunk covering the tank fuel pump wires, unplug the socket, go and bridge fuse 4 & 6. You should hear the pump under the car turn on. Now go plug the tank pump back in and you should hear it come on too.
6. Disconnect Engine Coolant Temperature sensor and try starting.
7. Disconnect the idle air control valve and try starting.
8. Ditto AMM.
9. Ditto O2 sensor.
10. I know you said sparkplugs were recently changed, and you just cleaned them. But if you got this far and nothing above worked, I suggest fitting completely new ones. Here's why:

a) You said the battery went flat at some stage. It may be weakened from all this cranking a non-starting car and producing a weak spark. You also said it ran, doesn't now, and you can smell fuel. That means the injector ground is pulsing ok, or they wouldn't be opening to spray fuel. But because the car isn't starting, the cylinders are ejecting that raw fuel out the exhaust - you can smell it. This means the cylinders could be flooded with fuel because the injectors keep spraying fuel in attempting to start the car as you crank.

This is what I was saying earlier about maybe being a combination of things. If the battery is providing a weak spark that would normally star the car, but the plugs become wet with fuel, that means no air in the sparkplug gap, so the spark gets 'drowned' = no start.

b) It's cheaper than a new distributor. And if it's not the plugs you can always use them at the next service.

Apart from that...

Again, when it's not starting, check the coil and injectors as above. Connect a 12V bulb across the two bare spade terminals of the coil (with all its wires still connected), crank engine, bulb should flash. Then do the same with one injector lead. (This is to check if those things are still present when the car won't start.) If they're ok, and if you can smell fuel (or a better confirmation like I said above is to pull one of those hoses on the fuel outlet off to confirm a decent flow of fuel is reaching the fuel rail)... then you know you have: a) fuel, and b) spark.

Btw... You can 'dry out' flooded cylinders by disconnecting all 4x injector wires, accelerator to the floor, crank engine for 20 seconds. If while cranking it nearly catches - behaves like it might have started, keep cranking until that stops, to clear all excess fuel. Then reconnect the injectors, and with NO accelerator pedal at all for at least several seconds after it catches, try starting. THEN try the feathering on the pedal to get the revs higher.

Btw... I'm not certain but that Ignition Control Module looks like it's mounted to a heatsink with thermal paste. i.e. If you confirm the car will start if you hit it with freezer spray, that means you'll be replacing it anyway. So it might be worth seeing if my suspicions are correct. Take it apart, see if it has thermal paste, remove it all, and put new stuff on for a few $ instead a new module. Similar to this: https://www.youtube.com/watch?v=-hNgFNH7zhQ - (But he's wrong, the X is actually better than the pea. Just make a smaller X than what he's done.) ;-p

Also:

http://www.volvowiringdiagrams.com/...s/Volvo Problem Solver Advanced Edition-1.pdf